A site in Kenya suggests that early members of the genus Homo used tool …

Given that chimps have demonstrated the ability to make and use tools in the wild, chances our that our human ancestors inherited some of that ability from the ancestor both humans and chimps have in common. But, starting with the australopithecines, our ancestors started making permanent tools from rocks, and investing increased effort into shaping. Oldowan tools were later used by the first members of the genus Homo, and were carried out of Africa during the global spread of Homo erectus.

By 1.4 million years ago, African Homo erectus was using the far more involved and sophisticated Acheulian tool technology, which later made its way out of Africa. But the transition between the two tool types has remained unclear. Now, scientists are reporting the first find where Oldowan and Acheulian tools have been found at the same site, one that's old enough to indicate that Acheulian tools were available when Homo erectus first left Africa.

The site in question lies near Lake Turkana in Kenya, which was already famous for finds relevant to human origins, including the Turkana Boy Homo erectus skeleton, which dates from 1.5 million years ago. The slopes near the northwest shore of the lake contain an extensive sedimentary record that can be matched with others in the nearby area, including some that have been dated using radioactive decay. A few meters below the sediments that contained the tools lies a feature that has been dated to 1.9 million years ago; above them, a different feature sets a younger limit at 1.5 million years. That last figure is rather significant, given that there are no reliably dated Acheulian tools older than 1.4 million years.

Extrapolating based on the depth of the deposits between, the authors estimate that the tools are roughly between 1.72 and 1.81 million years old. That lets them start zeroing in on a more precise date based on reversals in the Earth's magnetic field. This provides a firmer estimate: 1.76 million years, 350,000 years older than the previous site that had been dated so precisely. It also lines up with one of the earliest Homo erectus fossils, reinforcing the link between the two.

Since both toolmaking technologies were present in the same sediments, the site provides a clear indication that one set of techniques didn't simply replace the others. Either the Acheulian tools were developed by people who continued to use their earlier techniques, or the Acheulian technology was imported without its displacing the native one. In either case, the site suggests a more gradual transition than previous evidence had indicated.

The age of these tools also suggests that displacement was very, very gradual. It hadn't spread far enough to be in use by the first members of Homo erectus that left Africa at about the same time, and we don't have reliable dates on Acheulian tools in the Middle East that are much older than a million years. So, even if our ancestors were avid tool users, they weren't all that fond of adopting new technology.

I wonder if there was any brain development that was needed too? If it was literally hard to use the new tools, it might have slowed down their adoption and migration. They might travel at the pace of a gene sweep through the population rather than a new technological meme. I know of (popular) hypotheses about brain development and accurate throwing of rocks (or spears), I just wonder if we co-evolved with our tools?

It'd be nice to see an article summarizing the evolution of humans from our break with the chimps, at least enough to help me get all the different names in the right order, and to straighten out which branches we're directly descended from and which were our ancestors' contemporaries, which ones made it out of Africa and when, etc. My anthropology class was a long time ago. I mean, Wikipedia can help, but sometimes it's nice to have a straightforward narrative instead of having to sift through 15 different encyclopedia articles to stitch it all together. What do you think, John?

Getting a straightforward narrative is pretty hard in itself, just because the precise relationships between pre-modern human species is difficult to unravel. There's this page, which is probably somewhat out of date as the most recently discovered fossils mentioned are the hobbits (amazing how quickly our understanding can advance if that makes it "out of date," isn't it? Just shows how preliminary our knowledge is at this point).

According to the second article, "Loren Eiseley calculated[14] that Acheulean tools have an average useful cutting edge of 8 inches (20 cm) making them much more efficient than the 2 inch average of Oldowan tools."

Perhaps the bigger Acheulean tools were just too heavy to carry out of Africa?

What really happened was that Homo Erectus left his tools on the table at a restaurant. When he went back to get them, they were gone. He talked to Ung, the manager, who checked lost and found, but nobody had turned anything in. He tried to sue the restaurant for the value of the tools, but his lawyer (from the firm of Ergaster and Ergaster) was really stuck in the stone age.

Not necessarily in their heads, but you have to admit their sociocultural environment didn't exactly entice intellectual development...

We are able to see this even with very smaller time frames. Like fifty years. Fifty years ago people were duuuuuuumb... And we now are dumb compared to what our grandchildren will be. Or grandgrandchildren depending on your age.

Not necessarily in their heads, but you have to admit their sociocultural environment didn't exactly entice intellectual development...

We are able to see this even with very smaller time frames. Like fifty years. Fifty years ago people were duuuuuuumb... And we now are dumb compared to what our grandchildren will be. Or grandgrandchildren depending on your age.

On a serious note... this article is really insightful and interesting. I think I speak for all readers when I say that exciting content like this erectus like nothing else. I feel like you guys are all my homos.

Since when is creationists are allowed to make article on Ars?Those "tools" are created by intelligent human? Ridiculous! They are just funny-looking stones, shaped like that due to rain/wind/falling from cliff/any other coincidence.

Since when is creationists are allowed to make article on Ars?Those "tools" are created by intelligent human? Ridiculous! They are just funny-looking stones, shaped like that due to rain/wind/falling from cliff/any other coincidence.

According to the second article, "Loren Eiseley calculated[14] that Acheulean tools have an average useful cutting edge of 8 inches (20 cm) making them much more efficient than the 2 inch average of Oldowan tools."

Perhaps the bigger Acheulean tools were just too heavy to carry out of Africa?

I think you're misinterpreting. The Acheulean tools are bettter/more sophistocated because they make more efficient use of stone by providing a larger cutting edge per amount of stone. More of the stone is worked to create an effective cutting device, its not just a bigger rock.

The real find here is that the changeover was significantly gradual, with expertise in the Acheulean tools being only possessed by certain groups/individuals. I'd suggest that's evidence of cultural inertia more than anything else. (what previous posters allude to with the "Back in my day..." comments)

Lest you think I do not know this applies to me, I own a Kindle.1) At the bottom of 'the right page', I correctly turn the page, then look at the top of 'the left page'. There is no left page! There never will be a left page, I look there every time.

2) You can resize the text to suit your vision, so ALL books are large print books! But this means there are no page numbers. If there were page numbers every one who resized the font would have different page numbers from everyone else. I am embarrassed to 'miss' page numbers but I do. I get a percentage of the book I have read, which I am not used to. Just like that Monk.

:scratch: my internets has failed. What the hell is meant by ignore bomb (Other than the obvious intent to ignore.)? Or is this just another stupid meme like 'douche'?

Sorry, I was following Major General Thanatos' lead in using that term.

When I see a retard/fruitloop/creationist start posting the standard many-times-debunked schlock in these articles, I usually just add them to my ignore list (it's "add foe" in the Member List). It makes reading the comments in these kind of articles hugely more satisfying.

By "ignore bomb", I assumed Major General Thanatos was using colourful language to describe adding someone to his ignore list. I thought I'd jump on the wagon, since it sounded like a pretty cool term

I was about to add gramma to my ignore list when I got the joke - Ignore bomb averted!

First sentence of the article needs to be corrected. "Given that chimps have demonstrated the ability to make and use tools in the wild, chances our that our human ancestors inherited some of that ability from the ancestor both humans and chimps have in common." I think it is supposed to be "chances are" instead of "chances our."

One of the future advances in human evolution will be the proper use of homonyms. On the other hand, perhaps it will be just spelling all homonyms the same. When that happens, no longer will we be homo sapiens. Rather, we will be homo nymians!